Zivkovicia flexa  (Cash and Hopkinson, 1909) Ogden, 1983
Basionym: Pontigulasia compressa var. flexa  Cash and Hopkinson, 1909

Diagnosis: Shell narrower in proportion to its length, and with a much more oblique aperture than in the type, the neck having a considerable lateral flexure, and the aperture forming an angle of about 45 degrees with the general axis of the test. Surface of the shell is much smoother than in Z. compressa.

Dimensions: Cash and Hopkinson (1909): Length 140 µm; breadth in front view 80 µm, in lateral view 60 µm; diameter of aperture 25 µm.

Ecology: Fresh water. In Sphagnum.

Geographical distribution: Wales.

Remarks: Hopkinson (1909): “Empty tests only were found, but they differ so much from those of Pontigulasia compressa as hitherto seen that the form appears to merit at least varietal rank ; an opinion evidently held by Mr. Cash, who made the following brief remarks upon it:— “ bigibbosa? var.” “Mouth oblique (more so than in the type).” “ Probably distinct.”